[mirror_ubuntu-artful-kernel.git] / net / netfilter / nf_tables_core.c

/*
 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables_core.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_log.h>

static void nft_cmp_fast_eval(const struct nft_expr *expr,
			      struct nft_data data[NFT_REG_MAX + 1])
{
	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
	u32 mask;

	mask = ~0U >> (sizeof(priv->data) * BITS_PER_BYTE - priv->len);
	if ((data[priv->sreg].data[0] & mask) == priv->data)
		return;
	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
}

static bool nft_payload_fast_eval(const struct nft_expr *expr,
				  struct nft_data data[NFT_REG_MAX + 1],
				  const struct nft_pktinfo *pkt)
{
	const struct nft_payload *priv = nft_expr_priv(expr);
	const struct sk_buff *skb = pkt->skb;
	struct nft_data *dest = &data[priv->dreg];
	unsigned char *ptr;

	if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
		ptr = skb_network_header(skb);
	else
		ptr = skb_network_header(skb) + pkt->xt.thoff;

	ptr += priv->offset;

	if (unlikely(ptr + priv->len >= skb_tail_pointer(skb)))
		return false;

	if (priv->len == 2)
		*(u16 *)dest->data = *(u16 *)ptr;
	else if (priv->len == 4)
		*(u32 *)dest->data = *(u32 *)ptr;
	else
		*(u8 *)dest->data = *(u8 *)ptr;
	return true;
}

struct nft_jumpstack {
	const struct nft_chain	*chain;
	const struct nft_rule	*rule;
	int			rulenum;
};

static inline void
nft_chain_stats(const struct nft_chain *this, const struct nft_pktinfo *pkt,
		struct nft_jumpstack *jumpstack, unsigned int stackptr)
{
	struct nft_stats __percpu *stats;
	const struct nft_chain *chain = stackptr ? jumpstack[0].chain : this;

	rcu_read_lock_bh();
	stats = rcu_dereference(nft_base_chain(chain)->stats);
	__this_cpu_inc(stats->pkts);
	__this_cpu_add(stats->bytes, pkt->skb->len);
	rcu_read_unlock_bh();
}

enum nft_trace {
	NFT_TRACE_RULE,
	NFT_TRACE_RETURN,
	NFT_TRACE_POLICY,
};

static const char *const comments[] = {
	[NFT_TRACE_RULE]	= "rule",
	[NFT_TRACE_RETURN]	= "return",
	[NFT_TRACE_POLICY]	= "policy",
};

static struct nf_loginfo trace_loginfo = {
	.type = NF_LOG_TYPE_LOG,
	.u = {
		.log = {
			.level = 4,
			.logflags = NF_LOG_MASK,
	        },
	},
};

static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
				    const struct nft_chain *chain,
				    int rulenum, enum nft_trace type)
{
	struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);

	nf_log_packet(net, pkt->xt.family, pkt->ops->hooknum, pkt->skb, pkt->in,
		      pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
		      chain->table->name, chain->name, comments[type],
		      rulenum);
}

unsigned int
nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
{
	const struct nft_chain *chain = ops->priv;
	const struct nft_rule *rule;
	const struct nft_expr *expr, *last;
	struct nft_data data[NFT_REG_MAX + 1];
	unsigned int stackptr = 0;
	struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
	int rulenum = 0;
	/*
	 * Cache cursor to avoid problems in case that the cursor is updated
	 * while traversing the ruleset.
	 */
	unsigned int gencursor = ACCESS_ONCE(chain->net->nft.gencursor);

do_chain:
	rule = list_entry(&chain->rules, struct nft_rule, list);
next_rule:
	data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
	list_for_each_entry_continue_rcu(rule, &chain->rules, list) {

		/* This rule is not active, skip. */
		if (unlikely(rule->genmask & (1 << gencursor)))
			continue;

		rulenum++;

		nft_rule_for_each_expr(expr, last, rule) {
			if (expr->ops == &nft_cmp_fast_ops)
				nft_cmp_fast_eval(expr, data);
			else if (expr->ops != &nft_payload_fast_ops ||
				 !nft_payload_fast_eval(expr, data, pkt))
				expr->ops->eval(expr, data, pkt);

			if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)
				break;
		}

		switch (data[NFT_REG_VERDICT].verdict) {
		case NFT_BREAK:
			data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
			/* fall through */
		case NFT_CONTINUE:
			continue;
		}
		break;
	}

	switch (data[NFT_REG_VERDICT].verdict & NF_VERDICT_MASK) {
	case NF_ACCEPT:
	case NF_DROP:
	case NF_QUEUE:
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);

		return data[NFT_REG_VERDICT].verdict;
	}

	switch (data[NFT_REG_VERDICT].verdict) {
	case NFT_JUMP:
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);

		BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
		jumpstack[stackptr].chain = chain;
		jumpstack[stackptr].rule  = rule;
		jumpstack[stackptr].rulenum = rulenum;
		stackptr++;
		/* fall through */
	case NFT_GOTO:
		chain = data[NFT_REG_VERDICT].chain;
		goto do_chain;
	case NFT_RETURN:
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN);

		/* fall through */
	case NFT_CONTINUE:
		break;
	default:
		WARN_ON(1);
	}

	if (stackptr > 0) {
		if (unlikely(pkt->skb->nf_trace))
			nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN);

		stackptr--;
		chain = jumpstack[stackptr].chain;
		rule  = jumpstack[stackptr].rule;
		rulenum = jumpstack[stackptr].rulenum;
		goto next_rule;
	}
	nft_chain_stats(chain, pkt, jumpstack, stackptr);

	if (unlikely(pkt->skb->nf_trace))
		nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_POLICY);

	return nft_base_chain(chain)->policy;
}
EXPORT_SYMBOL_GPL(nft_do_chain_pktinfo);

int __init nf_tables_core_module_init(void)
{
	int err;

	err = nft_immediate_module_init();
	if (err < 0)
		goto err1;

	err = nft_cmp_module_init();
	if (err < 0)
		goto err2;

	err = nft_lookup_module_init();
	if (err < 0)
		goto err3;

	err = nft_bitwise_module_init();
	if (err < 0)
		goto err4;

	err = nft_byteorder_module_init();
	if (err < 0)
		goto err5;

	err = nft_payload_module_init();
	if (err < 0)
		goto err6;

	return 0;

err6:
	nft_byteorder_module_exit();
err5:
	nft_bitwise_module_exit();
err4:
	nft_lookup_module_exit();
err3:
	nft_cmp_module_exit();
err2:
	nft_immediate_module_exit();
err1:
	return err;
}

void nf_tables_core_module_exit(void)
{
	nft_payload_module_exit();
	nft_byteorder_module_exit();
	nft_bitwise_module_exit();
	nft_lookup_module_exit();
	nft_cmp_module_exit();
	nft_immediate_module_exit();
}
Commit	Line	Data
96518518 PM	1	/*
	2	* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/init.h>
	13	#include <linux/list.h>
	14	#include <linux/rculist.h>
	15	#include <linux/skbuff.h>
	16	#include <linux/netlink.h>
	17	#include <linux/netfilter.h>
	18	#include <linux/netfilter/nfnetlink.h>
	19	#include <linux/netfilter/nf_tables.h>
	20	#include <net/netfilter/nf_tables_core.h>
	21	#include <net/netfilter/nf_tables.h>
b5bc89bf	22	#include <net/netfilter/nf_log.h>
96518518	23
cb7dbfd0 PM	24	static void nft_cmp_fast_eval(const struct nft_expr *expr,
	25	struct nft_data data[NFT_REG_MAX + 1])
	26	{
	27	const struct nft_cmp_fast_expr *priv = nft_expr_priv(expr);
	28	u32 mask;
	29
	30	mask = ~0U >> (sizeof(priv->data) * BITS_PER_BYTE - priv->len);
	31	if ((data[priv->sreg].data[0] & mask) == priv->data)
	32	return;
	33	data[NFT_REG_VERDICT].verdict = NFT_BREAK;
	34	}
	35
c29b72e0 PM	36	static bool nft_payload_fast_eval(const struct nft_expr *expr,
	37	struct nft_data data[NFT_REG_MAX + 1],
	38	const struct nft_pktinfo *pkt)
	39	{
	40	const struct nft_payload *priv = nft_expr_priv(expr);
	41	const struct sk_buff *skb = pkt->skb;
	42	struct nft_data *dest = &data[priv->dreg];
	43	unsigned char *ptr;
	44
	45	if (priv->base == NFT_PAYLOAD_NETWORK_HEADER)
	46	ptr = skb_network_header(skb);
	47	else
c54032e0	48	ptr = skb_network_header(skb) + pkt->xt.thoff;
c29b72e0 PM	49
	50	ptr += priv->offset;
	51
	52	if (unlikely(ptr + priv->len >= skb_tail_pointer(skb)))
	53	return false;
	54
	55	if (priv->len == 2)
	56	(u16 )dest->data = (u16 )ptr;
	57	else if (priv->len == 4)
	58	(u32 )dest->data = (u32 )ptr;
	59	else
	60	(u8 )dest->data = (u8 )ptr;
	61	return true;
	62	}
	63
0ca743a5 PNA	64	struct nft_jumpstack {
	65	const struct nft_chain *chain;
	66	const struct nft_rule *rule;
b5bc89bf	67	int rulenum;
0ca743a5 PNA	68	};
	69
	70	static inline void
	71	nft_chain_stats(const struct nft_chain this, const struct nft_pktinfo pkt,
	72	struct nft_jumpstack *jumpstack, unsigned int stackptr)
	73	{
	74	struct nft_stats __percpu *stats;
	75	const struct nft_chain *chain = stackptr ? jumpstack[0].chain : this;
	76
	77	rcu_read_lock_bh();
	78	stats = rcu_dereference(nft_base_chain(chain)->stats);
	79	__this_cpu_inc(stats->pkts);
	80	__this_cpu_add(stats->bytes, pkt->skb->len);
	81	rcu_read_unlock_bh();
	82	}
	83
b5bc89bf PNA	84	enum nft_trace {
	85	NFT_TRACE_RULE,
	86	NFT_TRACE_RETURN,
	87	NFT_TRACE_POLICY,
	88	};
	89
	90	static const char *const comments[] = {
	91	[NFT_TRACE_RULE] = "rule",
	92	[NFT_TRACE_RETURN] = "return",
	93	[NFT_TRACE_POLICY] = "policy",
	94	};
	95
	96	static struct nf_loginfo trace_loginfo = {
	97	.type = NF_LOG_TYPE_LOG,
	98	.u = {
	99	.log = {
	100	.level = 4,
	101	.logflags = NF_LOG_MASK,
	102	},
	103	},
	104	};
	105
	106	static inline void nft_trace_packet(const struct nft_pktinfo *pkt,
	107	const struct nft_chain *chain,
	108	int rulenum, enum nft_trace type)
	109	{
	110	struct net *net = dev_net(pkt->in ? pkt->in : pkt->out);
	111
c9484874	112	nf_log_packet(net, pkt->xt.family, pkt->ops->hooknum, pkt->skb, pkt->in,
b5bc89bf PNA	113	pkt->out, &trace_loginfo, "TRACE: %s:%s:%s:%u ",
	114	chain->table->name, chain->name, comments[type],
	115	rulenum);
	116	}
	117
0ca743a5 PNA	118	unsigned int
0ca743a5 PNA	119	nft_do_chain_pktinfo(struct nft_pktinfo pkt, const struct nf_hook_ops ops)
96518518 PM	120	{
	121	const struct nft_chain *chain = ops->priv;
	122	const struct nft_rule *rule;
	123	const struct nft_expr expr, last;
	124	struct nft_data data[NFT_REG_MAX + 1];
96518518	125	unsigned int stackptr = 0;
0ca743a5	126	struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
b5bc89bf	127	int rulenum = 0;
0628b123 PNA	128	/*
	129	* Cache cursor to avoid problems in case that the cursor is updated
	130	* while traversing the ruleset.
	131	*/
	132	unsigned int gencursor = ACCESS_ONCE(chain->net->nft.gencursor);
96518518 PM	133
	134	do_chain:
	135	rule = list_entry(&chain->rules, struct nft_rule, list);
	136	next_rule:
	137	data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
	138	list_for_each_entry_continue_rcu(rule, &chain->rules, list) {
0628b123 PNA	139
	140	/* This rule is not active, skip. */
	141	if (unlikely(rule->genmask & (1 << gencursor)))
	142	continue;
	143
b5bc89bf PNA	144	rulenum++;
b5bc89bf PNA	145
96518518	146	nft_rule_for_each_expr(expr, last, rule) {
cb7dbfd0 PM	147	if (expr->ops == &nft_cmp_fast_ops)
cb7dbfd0 PM	148	nft_cmp_fast_eval(expr, data);
c29b72e0	149	else if (expr->ops != &nft_payload_fast_ops \|\|
0ca743a5 PNA	150	!nft_payload_fast_eval(expr, data, pkt))
0ca743a5 PNA	151	expr->ops->eval(expr, data, pkt);
cb7dbfd0	152
96518518 PM	153	if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)
	154	break;
	155	}
	156
	157	switch (data[NFT_REG_VERDICT].verdict) {
	158	case NFT_BREAK:
	159	data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
	160	/* fall through */
	161	case NFT_CONTINUE:
	162	continue;
	163	}
	164	break;
	165	}
	166
e569bdab	167	switch (data[NFT_REG_VERDICT].verdict & NF_VERDICT_MASK) {
96518518 PM	168	case NF_ACCEPT:
	169	case NF_DROP:
	170	case NF_QUEUE:
b5bc89bf PNA	171	if (unlikely(pkt->skb->nf_trace))
	172	nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
	173
96518518	174	return data[NFT_REG_VERDICT].verdict;
e569bdab EL	175	}
	176
	177	switch (data[NFT_REG_VERDICT].verdict) {
96518518	178	case NFT_JUMP:
b5bc89bf PNA	179	if (unlikely(pkt->skb->nf_trace))
	180	nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RULE);
	181
96518518 PM	182	BUG_ON(stackptr >= NFT_JUMP_STACK_SIZE);
	183	jumpstack[stackptr].chain = chain;
	184	jumpstack[stackptr].rule = rule;
b5bc89bf	185	jumpstack[stackptr].rulenum = rulenum;
96518518 PM	186	stackptr++;
	187	/* fall through */
	188	case NFT_GOTO:
	189	chain = data[NFT_REG_VERDICT].chain;
	190	goto do_chain;
	191	case NFT_RETURN:
b5bc89bf PNA	192	if (unlikely(pkt->skb->nf_trace))
	193	nft_trace_packet(pkt, chain, rulenum, NFT_TRACE_RETURN);
	194
	195	/* fall through */
96518518 PM	196	case NFT_CONTINUE:
	197	break;
	198	default:
	199	WARN_ON(1);
	200	}
	201
	202	if (stackptr > 0) {
b5bc89bf PNA	203	if (unlikely(pkt->skb->nf_trace))
	204	nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_RETURN);
	205
96518518 PM	206	stackptr--;
	207	chain = jumpstack[stackptr].chain;
	208	rule = jumpstack[stackptr].rule;
b5bc89bf	209	rulenum = jumpstack[stackptr].rulenum;
96518518 PM	210	goto next_rule;
96518518 PM	211	}
0ca743a5	212	nft_chain_stats(chain, pkt, jumpstack, stackptr);
96518518	213
b5bc89bf PNA	214	if (unlikely(pkt->skb->nf_trace))
	215	nft_trace_packet(pkt, chain, ++rulenum, NFT_TRACE_POLICY);
	216
0ca743a5	217	return nft_base_chain(chain)->policy;
96518518	218	}
0ca743a5	219	EXPORT_SYMBOL_GPL(nft_do_chain_pktinfo);
96518518 PM	220
	221	int __init nf_tables_core_module_init(void)
	222	{
	223	int err;
	224
	225	err = nft_immediate_module_init();
	226	if (err < 0)
	227	goto err1;
	228
	229	err = nft_cmp_module_init();
	230	if (err < 0)
	231	goto err2;
	232
	233	err = nft_lookup_module_init();
	234	if (err < 0)
	235	goto err3;
	236
	237	err = nft_bitwise_module_init();
	238	if (err < 0)
	239	goto err4;
	240
	241	err = nft_byteorder_module_init();
	242	if (err < 0)
	243	goto err5;
	244
	245	err = nft_payload_module_init();
	246	if (err < 0)
	247	goto err6;
	248
	249	return 0;
	250
	251	err6:
	252	nft_byteorder_module_exit();
	253	err5:
	254	nft_bitwise_module_exit();
	255	err4:
	256	nft_lookup_module_exit();
	257	err3:
	258	nft_cmp_module_exit();
	259	err2:
	260	nft_immediate_module_exit();
	261	err1:
	262	return err;
	263	}
	264
	265	void nf_tables_core_module_exit(void)
	266	{
	267	nft_payload_module_exit();
	268	nft_byteorder_module_exit();
	269	nft_bitwise_module_exit();
	270	nft_lookup_module_exit();
	271	nft_cmp_module_exit();
	272	nft_immediate_module_exit();
	273	}